This invention relates to interfitting apparatus which enables at least one shaft member and at least one hole formed in an object, such as a bearing and a bearing box and a piston and a piston cylinder, to be interfitted with each other with a high degree of precision.
U.S. Pat. No. 3,824,674 discloses a tactile sensation interfitting apparatus which is known as an example of the prior art for interfitting a shaft and a hole with each other. More specifically, in this apparatus, a shaft portion is gripped by a clamping device including a spring or other soft object and a tactile sensor for detecting the manner of contact of the shaft portion with the hole portion. The relative positions of the shaft portion and the hole portion and their posture are calculated, and a predetermined probing operation is carried out according to the relations, so as to bring the shaft portion near to the hole portion. Then the shaft portion is forced against the hole portion while judging, by means of the sensor, whether or not the fitting is in progress. If the shaft portion is not fitted in the hole portion. Then, a predetermined probing operation for fitting the shaft portion in the hole portion is conducted so as to fit the former into the latter. The present practice of interfitting two members with each other is to use, as aforesaid, a system which combines the shaft clamping device including a spring and a sensor with a probing control using a sensor and an X-Y table. By this system, interfitting of a shaft and a hole with each other with a margin in the order of microns has been carried out by relying on what may be referred to as a tactile sensation robot. Some disadvantages are associated with this apparatus. Since the tactile sensation interfitting apparatus effects interfitting by performing a probing action under the control of the sensor and X-Y table, a mechanism for the X-Y table must be provided and at the same time a complex control system must be used for the sensor and the X-Y table. Thus the apparatus is both low in reliability and high in cost.
In the aforesaid tactile sensation apparatus of the prior art, it is impossible to perform so-called multishaft interfitting in which two or more shafts are simultaneously fitted in respective holes fixed relative to one another, because the shaft portions are each held by a clamping device comprising a spring or other soft object for free movement and it is impossible to effect positioning of the shafts and the holes with a sufficiently high precision to allow smooth interfitting. Assuming that this tactile sensation interfitting apparatus is used for effecting multishaft interfitting by fitting the shafts not simultaneously but one after another, it would be possible to effect interfitting of the first shaft and the first hole with each other, but the second shaft et. seq. could not be fitted in the holes because the shafts are mechanically restrained relative to one another as aforesaid and the fact that the clamping devices for the shafts are interconnected by the medium of springs or other soft objects makes it impossible to perform a probing operation.